宽幅波纹钢腹板预应力混凝土箱梁的空间力学性能研究

The most important feature of composite box girder with corrugated steel webs is that the web is made of corrugated steel plates, which makes the cracks of concrete web never appear and the stability of panals improved. The prestress loss of girder is also reduced for its low axial stiffness due to the accordation-like behavior. This kind of steel-concrete composite structure is known for the explicit mechanical behavior, constrution convenience and well seismic performance. As the traffic is increasing with a high rate, the bridge structures are built wider and wider, so the box girder with several cells may be applied in the wide composite girder with corrugated steel webs. However, the domestic and foreign researchers are almost focus on static and dynamic performances of the composite box girder with only one cell. In this project, the spatial mechanical behaviors of wide composite box girder with corrugated steel webs will be studied. Based on scaled-model experiments, theoretic analysis and finite element analysis, three kinds of prestressed concrete composite box-girders with corrugated steel webs will be modeled, including single-box with single-cell, double-cell and three-cell. The shear lag effect of top and bottom slab, the distribution of shear force in different corrugated webs and the transverse bending behavior will be studied. The load transfer mechanism of wide composite box-girders with corrugated steel webs will be revealed. The equations for the effective distribution width and the shear force distributing will be proposed, and the design theory of the transverse bending behavior will be put forward.

波纹钢腹板-混凝土组合箱梁最大的特点是以波纹钢板作为箱梁的腹板，不仅避免了混凝土腹板的开裂问题，提高了钢腹板抗屈曲能力，而且因其轴向刚度很小，减小了预应力损失，是一种受力明确、施工便捷、抗震性能优越的钢-混组合结构。为适应快速增长的交通流量，波纹钢腹板-混凝土组合箱梁可采用单箱多室的宽幅箱梁结构。但目前，国内外研究主要集中在单箱单室波纹钢腹板组合箱梁的静动力性能，对于宽幅组合箱梁的研究不足，不利推广应用。本项目将对宽幅波纹钢腹板-预应力混凝土箱梁的空间力学性能展开深入研究。以单箱单室、双室和三室波纹钢腹板组合箱梁为主要研究对象，在缩尺模型试验、理论分析和有限元数值分析的基础上，对宽幅波纹钢腹板-预应力混凝土箱梁的顶底板剪力滞效应、波纹钢腹板剪力分配和箱梁横向受力进行研究，揭示宽幅组合箱梁的空间受力机理。提出宽幅波纹钢腹板组合箱梁有效分布宽度和腹板剪应力的计算公式，建立横向弯曲受力设计理论。

波纹钢腹板-混凝土组合箱梁可以避免混凝土腹板开裂，且具有钢腹板抗屈曲能力好、预应力损失小、施工便捷、抗震性能优越等优点。本项目制作了单箱单室、双室和三室波纹钢腹板组合箱梁缩尺模型，通过模型试验结合理论分析和有限元数值分析的方法，对宽幅波纹钢腹板-预应力混凝土组合箱梁的空间力学性能展开深入研究。研究了单箱多室波纹钢腹板组合箱梁的弯曲、扭转受力性能，掌握了混凝土顶底板剪力滞效应和波纹钢腹板剪力分配的规律，发现单箱多室波纹钢腹板组合箱梁的受力除包括截面整体弯曲、扭转外，还存在箱室局部畸变引起效应，各箱室的局部畸变效应使剪力滞效应的规律以及钢腹板剪力分布与单室箱梁有明显区别，必须考虑荷载横向作用位置的影响；中横隔板的设置对混凝土顶底板正应力和钢腹板剪应力分布的影响不能忽略；对宽幅单箱单室和单箱多室波纹钢腹板组合箱梁横向受力进行研究，结果表明现行规范在计算宽度较大的该类组合箱梁的横向应力偏不安全，而单箱多室组合箱梁的横向应力可简化为对应单室箱梁进行计算；通过进行详细的参数分析，提出单箱三室波纹钢腹板组合箱梁剪力滞系数和有效分布宽度的实用计算公式；提出了单箱多室波纹钢腹板组合箱梁腹板剪应力的计算方法；对宽幅单箱单室和单箱多室波纹钢腹板组合箱梁横向应力计算方法进行了修正。本项目研究成果可为宽幅波纹钢腹板组合箱梁设计计算提供参考，为国家或行业设计标准的编制提供依据，有助于推动波纹钢腹板组合箱梁在我国的发展应用。